The present invention relates generally to the field of inflatable devices for supporting the human body, and more particularly is concerned with an inflatable foot cushion to counter the force amplifications experienced by the foot, and particularly the heel area of the foot, when the body is in the supine position.
In the supine position, the foot assumes the shape of a wedge that tapers from the toes down to the heel. The force amplifications that are typically associated with a wedge are therefore also experienced by the wedge-shaped foot. The heel area, and more specifically the points of contact between the heel area and the substrate upon which the body is lying in the supine position, experiences force amplifications analogous to those experienced by the working edge of the typical wedge. In addition, when in the supine position, the lower legs function as levers with the heel areas serving as fulcrums, further amplifying the forces acting upon the foot.
These force amplifications associated with the foot, and particularly the heel area of the foot, increase the danger to the soft tissues of the foot and heel areas by, increasing the likelihood of decubitus ulcer formation, for example. Heretofore, devices for preventing the formation of decubitus ulcers on the heel area have not effectively countered these force amplifications experienced by the foot when the body is in the supine position. Merely elevating the foot with a pad, or the like, to suspend the heel area above the substrate upon which the body is lying in the supine position, simply transfers the force amplifications from the heel area to the area of contact between the pad and the ankle or lower leg area. The new area of contact would still be the fulcrum for the lever-like action of the lower leg, and now also the foot. Alternatively, merely wrapping the foot and lower leg areas with padding is equally unsatisfactory if the circumferential contacts of the padding and means for securing the padding to the foot and lower leg areas restrict the blood flow to the lower leg and foot.